At present, a boom is a common upper structure used on the special vehicles. The boom usually needs to do extension/retraction, revolution, or translation movement when it's working. If the boom has vibration in the revolution direction during the movement, not only the normal operation of the upper structure may be affected, but also the service life of the boom or upper structure may be shortened, and even accidents may occur.
For example, on a concrete pump truck, the boom is a slender and flexible cantilever beam structure formed by several sections articulated together. If severe vibration occurs in the revolution direction when the boom is revolving or the concrete is being pumped, not only the service life of the structural parts of the pump truck will be shortened, but also severe personal injury accidents may occur. Therefore, it is of great significance to effectively suppress vibration of the boom, especially the vibration of the boom in the revolution direction, in order to improve operation safety of the boom.
For example, on a concrete pump truck, usually the pumping gear is shifted down to decrease the pumping rate and pumping efficiency, or the attitude of the boom is changed, so as to adjust the inherent frequency of the boom. However, the above method are time and labor consuming, and affect construction period.
In addition, there's another method changing the form of operating current of the revolving mechanism at starting/baking of the revolving operation, e.g., changing square wave to the form of sloped square wave or increasing the slope rate to buffer the vibration; however, that method does not only increase the time of revolving operation of the boom; more adversely, owing to the existence of the sloped revolving operating current, the boom will revolve further to some distance even though the pump truck operator has issued a braking signal. Therefore, a potential safety hazard still exist.